1. Field of the Invention
This invention relates to axle assemblies for road vehicles.
2. Summary of the Invention
According to the invention, we provide an axle assembly for a road vehicle, comprising an axle beam having oppositely disposed limbs, means constraining the centre of the axle beam to translatory movement in a plane extending fore and aft of the vehicle while permitting universal pivoting of the axle beam, aligned spindles received in the end portions of the limbs of the beam to extend transversely of the vehicle, a hub carried by each spindle, an arm carried by each spindle extending generally upwardly therefrom, and at least one radius rod on each side of the vehicle, the or one radius rod being connected to each arm at a position remote from the spindle.
The means constraining the centre of the axle may comprise a V shaped link having its apex connected to the axle beam adjacent the centre thereof by a universal coupling, and its base pivotally connected to the chassis of of the vehicle for movement about an axis extending transversely of the vehicle.
Preferably an upper and a lower radius rod is provided at each side of the vehicle, a lower radius rod on each side being connected to the axle assembly adjacent to the spindle on that side and the other radius rod being connected to the arm on that side at its upper end remote from the spindle.
Each arm extends inboardly of the vehicle chassis and at an inclination to the longitudinal axis of the spindle. The spindle, the arm and a further vertical link may form a triangular arrangement.
The hubs can be driven by shafts extending between them and gearboxes on hubs carried by the spindles. The gearboxes (which may be of any desired ratio) will normally contain bevel gears so that the hubs can be driven from shafts extending generally longitudinally of the vehicle. Alternatively the hubs are driven from separate shafts connected to a differential final drive, the shaft extending, for example, obliquely to the centre line of the vehicle.
The hubs may be steered. For this purpose, the spindles on which the hubs are mounted may be hollow and may have control rods located therein, the control rods being connected to track rods which pass out of the spindles through slots in the walls thereof and which are connected to the hubs by steering arms. Steering is effected by moving the control rods longitudinally within the spindles. The control rods may project inwardly from the spindles and be controlled by separate quadrants or pinions so as to leave a clear space between the limbs of the axle beam in which the engine and/or gearbox of the vehicle can be accommodated.
If desired, the hollow spindles may form cylinders for pistons and be connected to a source of hydraulic fluid so as to provide a power steering arrangement.